This invention relates in general to a water distribution system for spraying of water onto an ice forming surface of an ice making machine, and is more particularly concerned with such water distribution apparatus which provides a fine and uniform spray of water onto the ice forming surface from a plurality of orifices defined in a cylindrical spraying means, the spraying means being substantially shielded except for at least one opening in the shielding means through which the fine water streams are sprayed, the spraying means being rotatable in the shielding means, as by a turbine blade assembly in a hydraulically driven turbine.
Various types of ice cube making machines for forming crystal clear ice cubes are known to the prior art. Such crystal clear ice cubes are usually more appealing to consumers than the cloudy appearing cubes, such as those cubes obtained from freezing water in ice cube trays. The cloudy appearance of conventional cubes formed by freezing water in trays results from entrapped dissolved gases coming out of solution from the water during freezing and from impurities trapped in the freezing water. Crystal clear ice cube forming machines have heretofore enjoyed considerable popularity in many commercial establishments, such as, for example, in hotels, restaurants or the like. More recently, a significant and growing market for smaller versions of these commercial ice cube making machines has come into being with these smaller "residential" machines compatible for use in offices and the like as well as in homes.
It is known in the prior art ice cube making machines to have an inverted ice cube forming tray with a plurality of individual ice cube forming cups thermally connected to an evaporator coil of the refrigeration system. The ice cube forming cups are usually metallic for good heat transfer to the evaporator coils. Cold water of about 32.degree. F. is continually sprayed into the ice cube forming cups, as by a nozzle disposed below each cup. Since the cups are maintained at a temperature below the freezing point of water by the evaporator coils, ice is continually formed in the ice cube forming cups until a complete cube is formed in each of the cups. At this time, the cups are warmed to a temperature above the freezing point of water, as by passing warmer tap water about the top side of the ice cube forming cups such that the outer surface of each cube in contact with its cup melts and the cubes thereupon fall from the inverted cups.
In spraying of water into the ice cube forming cups during formation of the ice cubes, it has been common practice to employ a plurality of fixedly mounted nozzles disposed below the ice cube forming cups, as on a water supply line, to continuously spray water onto and into the cups. Since it has not heretofore been thought economical to provide a separate nozzle for each of the cups, it is also known to design the nozzle to provide a single, broad stream of water to a plurality of cups. For example, five spraying nozzles may accommodate fifteen ice cube forming cups by each of the nozzles having a thin and elongated orifice such that a single stream of water from each nozzle simultaneously sprays three adjacent ice cube forming cups. While such an arrangement is more economical from a manufacturing standpoint, it has operational shortcomings. The continuous and substantial volume of water from such an orifice has a substantial melting effect upon layers of ice already formed in the ice cube forming cups. This substantial stream of water is further not easily or effectively broken down or atomized into tiny water droplets. Tiny droplets promote faster and more efficient formation of ice in the ice cube forming cups than from a continuous stream of water since heat is readily transferred from the tiny droplets of cold water to form ice before the water droplet has had a chance to flow away from the ice forming areas.
Some attempts have been made to mount directional spraying nozzles on a reciprocating spraying arm with the arm reciprocatingly moved through an angular arc to spray water in fine droplets onto an ice cube forming surface. These attempts have not met with commercial success since electric motors are prone to fail in the high humidity conditions encountered in the ice making machine. Furthermore, this type of arrangement is not operationally efficient since only a smaller portion of the ice cube forming surface is being sprayed at any given moment. Of course, it is also dangerous to use any electrical equipment, such as a motor, in the high humidity spraying area of the ice cube machine because of possible electrical shock hazards which may result to the machine users.
The prior art nozzle sprayers are also prone to partial or complete orifice blockage due to buildups of sediments and minerals. Of course, during total orifice blockage no ice cubes are formed in the cups associated with the blocked nozzles. Malformed ice cubes result from partial orifice blockage. Partial nozzle blockage, therefore, results in reduced ice cube production. The cost of maintenance and repair to periodically correct such problems is, of course, substantial, especially in view of the initial cost of a residential type ice cube making machine.
It is, therefore, a primary object of the present invention to provide a fine spray directed within a predetermined angular arc onto an ice cube forming surface wherein the entire ice cube forming surface is continuously sprayed by fine water streams from many orifices for each ice cube forming cup.
A related object of the present invention is to provide a spraying unit for spraying fluid in a predetermined direction from the spraying unit onto a surface in spaced relation from the spraying unit wherein the spraying unit includes a rotatable spraying tube with a plurality of orifices extending into a hollow interior of the spraying tube and shielding means disposed about the rotatable spraying tube with at least one opening defined through the shielding means through which fluid may be sprayed through those orifices which are not shielded by the shielding means, and means for rotating the spraying tube such that the fine streams of fluid from the orifices continuously move or sweep across the surface being sprayed.
A further object of the present invention is to provide spraying apparatus for an ice cube making machine which provides a self-cleaning action for keeping the orifices free of partial or complete blockage from sediment or mineral deposits.
Yet another object of the present invention is to provide such spraying apparatus wherein the rotatable spraying means is driven by a turbine also operated from fluid or water pressure and having a high degree of reliability, few moving parts and economy of manufacture.
A further object of the present invention is to provide spraying apparatus for dispersing the sprayed water into a finer and moving spray which operates from lower input water pressures such that the time to form crystal clear ice cubes in an ice making machine is substantially reduced and the attendant operating efficiency and ice cube making capability of the machine are substantially enhanced.
These advantages of the invention, and others, including those inherent in the invention, are provided by spraying apparatus for continuously spraying fine streams of fluid within a predetermined angular arc from the spraying apparatus onto a surface in spaced relation from the spraying apparatus. The spraying apparatus includes rotatable spraying means with a plurality of orifices extending into a hollow interior of the spraying means, the hollow interior of the spraying means communicating with a supply of fluid to be sprayed, shielding means disposed about the rotatable spraying means with sufficient operational clearance between the spraying means and the shielding means to permit said spraying means to be rotated within said shielding means, the shielding means having at least one open area defined therein through which fluid may be sprayed through those orifices of the spraying means at the open areas which are not shielded by the shielding means, and means for rotating the spraying means such that fluid is sprayed from the spraying means through the open area in the shielding means in a plurality of fine streams which continually sweep across the surface being sprayed. The rotatable spraying means preferably comprises an elongate and hollow cylindrical tube with a plurality of apertures defined therethrough. The cylindrical tube is closed at one end and opened at an opposite end for communication with a pressurized supply of fluid. The shielding means preferably comprises another hollow tube of slightly larger inside diameter than the outside diameter of the spraying tube, the shielding tube having at least one cut out or open area defined therethrough such that fluid may be sprayed through those orifices of the spraying tube which are not shielded by the shielding tube. The shielding tube is also closed at the same end as the spraying tube and has an opposite end suitable for adjusting the angular position of the cut out or open area to adjust the direction of spray.
The means for rotating the spraying means preferably comprises a turbine also driven by fluid pressure. The turbine includes a housing with a water inlet and a water outlet and in which a turbine blade assembly is rotatably disposed. The turbine blade assembly is operatively connected to the spraying means to rotatably drive the same. An aperture is defined in the turbine housing through which the spraying tube extends to the turbine blade assembly. An end cover or the like encloses an opposite side of the turbine housing. The end cover has an aperture defined therethrough for communication of a source of fluid pressure with the hollow interior of the spraying tube and further provides a bearing for the open end of the spraying tube. Pressurized water at the turbine housing water inlet causes rotation of the turbine blade assembly, and hence the spraying tube, and the water is thereafter expelled through the water outlet of the turbine housing in a substantially unpressurized condition.